That is totally wrong. In fact the MiFiD II EU financial regulations that are coming into force in 2018 say that any country can essentially be passported into

That is totally wrong. In fact the MiFiD II EU financial regulations that are coming into force in 2018 say that any country can essentially be passported into the block as long as they have an "equivalent" regulatory regime. http://www.cnbc.com/2016/07/07/theres-a-little-known-eu-rule-that-may-stop-the-brexit-banking-exodus.html http://www.cnbc.com/2016/07/07/theres-a-little-known-eu-rule... So your statement that such companies "can't expect" is wrong - in fact they can expect that, because the EU already committed to it. This is posing a big problem for the EU right now because obviously on the day of exit the UK would still have an "equivalent" regime, so there'd be no grounds to force bankers to relocate. The details of MiFiD II were handled by technocrats whose brief was just to make trade easier, so such rules make sense: if the two regimes are close enough, why insist on EU membership? Nobody realistically expects the EU to stick to their own rules though. The EU never lets written law trump political demands. Just look at the Euro bailouts if you doubt that.